Dual hook block hoists



Aug. 1, 1961 M. R. BOWERMAN vEl AL DUAL HOOK BLOCK HOISTS 2 Sheets-Sheet 1 Filed Sept. 29, 1959 VINVENTORS Myron R. Bowermon 8 Richard L. Sruckey 1961 M. R. BOWERMAN ETAL 2,994,513

DUAL HOOK BLOCK HOISTS 2 Sheets-Sheet 2 Filed Sept. 29. 1959 Fig.7.

INVENTORS Myron R. Bowermcn 8: Richard L. Stuckey United States Patent Filed Sept. 29, 1959, Ser. No. 843,212 7 Claims. (Cl. 254-468) This invention relates to dual hook block hoists and particularly toa dual hook block operable as two separate parts from a single drive.

There are frequently instances where it is desirable to have a fast moving light hook block operable on the same crane with a heavy duty, heavy load carry hook. In the past this has necessitated two separate drive systems and two separate hoisting drums. Generally, these two hoisting drums and drive units were spaced apart on the crane frame, requiring heavier load bearing members as well as the additional expense of the second hoisting system.

We have invented a double block hoist structure which provides both a light duty fast operating hook block independently operable on the same hoisting mechanism as the main heavy duty block. We preferably provide a crane frame, a hoisting drum on said frame, drive means on the frame for driving the hoisting drum, a cable on said drum extensible and retractable by rotation of said drum, spaced sheave means on the main frame on parallel axes, a main hook block, a main hook on said block, sheave means in said hook block receiving said cable in multiple reeving with the sheave, means on the main frame whereby said main hook block depends from said main frame, a secondary hook block spaced from the main hook block and receiving said cable from one of said spaced shaves, means on the frame whereby said secondary hook block depends from the main frame, locking means 'on the main frame releasably locking the main hook block thereto whereby to selectively hold said main hook block against movement relative to the main frame and permit independent movement of the secondary hook block.

In a preferred form of our invention we provide two cables on the drum fixed at one end to the drum, reeved over the sheaves on the frame and on the main and secondary hook blocks and fixed at the other end to an equalizing bar on the main frame.

In the foregoing general description we have set out certain objects, advantages and purposes of our invention. Other objects, advantages and purposes will be apparent from a consideration of the following description and the accompanying drawings in which FIGURE 1 is a side elevation of a crane embodying the dual hook block structure of this invention;

FIGURE 2 is a schematic View of the sheave arrangement of the structure shown in FIGURE 1;

FIGURE 3 is a top plan view of the sheave arrangement shown in FIGURE 2 on the line I11HI;

FIGURE 4 is a section on the line IV-IV of FIG- URE 2;

FIGURE 5 is a section on the line VV of FIG- URE 3;

FIGURE 6 is a transverse section through the main hoist block of a second embodiment of our invention; and

FIGURE 7 is a transverse section through the sec ondary hoist block of the embodiment of FIGURE 6.

Referring to the drawings, we have illustrated a conventional crane trolley 10 movable on wheels 11 on tracks 12 of crane girders 13. The crane girders 13 are in turn movable on tracks 14 on the main building frame. The trolley 10 is provided with a main frame 15 carrying a hoisting drum 16 driven by a drive motor 17 in conventional fashion. Three sets of sheaves are provided on the main frame on spaced parallel shafts '18, 19 and 20 parallel to the axis of the ,hoist drum 16. Two sheaves 21 are provided on shaft 118. Two pairs of sheaves 22, 23 are provided on the intermediate shaft 19 and two sheaves 24 are provided on shaft 20. A main hook block 25 carrying sheaves 26a, 26b and 260 depends from hoisting cables 27, 28. A secondary hook block 29 depends on sheaves 30 from the same cable but on a spaced apart axis. The cables 27, 28 are reeved under sheaves 26a on the main hook block. From sheaves 26a they pass over sheaves 23 on the main frame, from sheaves 23 under sheaves 30 on the secondary block. From sheaves 30 the cables are returned over sheaves 24 on the main frame and thence over sheaves 22 then over sheaves 26b on the main hook block 25, then over sheave 21 on the main frame, under sheaves 26c on the main hook block 25 and are fixed at their free ends to the equalizer 31 which is pivotally attached to the main frame. The main hook block 25 is provided with lugs 32 extending outwardly from each side. These lugs 32 are engaged by latches 33 movable on the main trolley frame by means of solenoids (not shown) or similar actuating mechanisms. 'Ihese latches may be operated pneumatically, manually, electrically or by any other suitable Well known means.

When it is desired to operate the secondary hook block 29 the main hook block 25 is raised to the point where the latches 33 engage and hold the lugs 32. Rotation of the drum 16 to pay out cables 27 and 28 through sheaves 26a, 23 and 24 and 30 will then lower the secondary hook block 29 Without movement of the main hook block. When it is desired to use the main hook block 25 the secondary hook block 29 is raised into contact with the trolley frame, the latches 33 are released and the weight of the main hook block holds the secondary hook block in position.

If by chance the secondary hook block is in the lowered position when the main hook block is released the weight of the main hook block will immediately raise the secondary hook block into contact with the main frame. In order to prevent this an interlock system may be used in conjunction with latches on the secondary hook block. We have illustrated such a device in FIGURES 6 and 7. In FIGURES 6 and 7, we have shown a secondary hook block 29' depending below the main frame. Parts corresponding to those of the first embodiment are g ven the same reference characters but with a prime added thereto. Latches 40 are pivoted on shafts 41 on the frame and are urged toward the closed position by springs 42 acting on crank arms 42a. When the block 29 is raised, it contacts plunger 43 which rises until it indexes itself in notches 44 of weight block 45. As block 29' continues to rise it raises the weight block 45 and permits rollers 46 to run down inclined surfaces 45a on block 45 until the notches 40a, in the latches 40, engage flanges 47 on block 29'. At the same time, limit switch weight 48 is raised and the limit switch (not shown) is tripped. When the drum is next rotated to pay out the lowering cables, block 29' is prevented from lowering by latches 40. The main hoist block 25' is lowered, at the same time, weight 49 moving in housing 50, is lowered. Weight 49 is connected to weight 45 by cables 51 which pass over sheaves 52 and 53 on the frame, thus causing weight 45 to rise to its highest position allowing the plunger 43 to index itself to the next position. As the weight 49 lowers, the limit switch weight 54 is also lowered and acts to reset the limit. switch. Weight 54 is connected to the switch by means of cable 55 passing over sheaves 56 and-57 on the frame. When the main block 25' is returned, it will engage the counter-weight 49 raising it and lowering weight 45 until the plunger 43 engages the top of auxiliary Patented Aug. 1, 1961 3 block 29. Further lowering of weight 45 causes the plunger 43 to turn so that the weight 45 lowers around it. As the weight 49 nears the top of its stroke it raises the switch-Weight 54 tripping the limit switch. By this time the weight 45 will have reached the bottom of its stroke and will open the latches 40. The auxiliary block 29' will then drop, taking up slack cable until the main hoist block 25' is tight to the frame. pays out rope, the secondary block 29 is lowered allowing the plunger 43 to drop to its lowermost position at which time the limit switchweight 48 drops, resetting the limit switch.

The present arrangement of main and secondary hook blocks makes it possible to operate the secondary hook block with the minimum of sheave movement in the main hook block and with a minimum of cable movement through the main hook block. This sheaving arrangement is important for the reason that it reduces the wear on the cables as Well as the resistance to movement and therefore the loss of energy occurring when all of the sheaves move in both hook blocks on the main frame.

While We have illustrated and described a presently preferred embodiment of our invention it will be understood that this invention may be otherwise embodied within the scope of the following claims.

We claim:

1. A dual block hoist structure comprising a main crane frame, a hoisting drum on said frame, drive means on the frame for driving the hoist drum, a cable on said drum extensible and retractable by rotation of'said drum, spaced sheave means on said main frame on three parallel axes on one side of the drum, one axis adjacent the drum, one axis remote from the drum and one axis intermediate the adjacent and the remote axes, a main hook block, a main hook on said block, sheave means on said mainhook block receiving said cable in multiple reeving with said sheave means on said main frame whereby said main book block depends from said main frame, a

secondary hook block spaced from said main hook block and receiving said cable from one of said spaced sheave means on said frame whereby said secondary hook block depends from said main frame, locking means on said main frame releasably holding said main hook block thereto whereby to selectively hold said main block against on the frame for driving the hoist drum, a cable on said drum extensible and retractable by rotation of said drum, spaced sheave means on the main frame on three parallel axes on one side of the drum, one axis adjacent the drum, one axisremote from the drum and one axis intermediate tlie' adjacent and the remote axes, a main hook block, a main hook on said block, sheave means in said main hook block receiving said cable from said drum, and passing it toi sheave means on said intermediate sheave axis on said main frame whereby said main hook block depends from said main frame, said cable passing therefrom to a sheave on said axis remote from said drum, a secondary hook block spaced from said main hook block and receiving said cable from said sheave" means on said remote axis and returning it to a second sheave on said intermediate axis whereby said secondary hook blockidepends from said main frame,tsaid cablepassing" from said second sheave to a sheave on said main hook tive' to the frame, and means selectively operating said locking means.

As the drum 3. A dual block hoist structure comprising a main crane frame, a hoisting drum on said frame, drive means on the frame for driving the hoist drum, a cable on said drum extensible and retractable by rotation of said drum, three spaced parallel sheave axes on said frame generally parallel to and on oneside of the drum, one adjacent the drum, one remote from the drum and oneintermediate the'adjacent and the remote axes, a mainhook block, a main hook on said block, sheave-means in said main hook block, sheave means on said sheave axis adjacent said drum receiving said' cable in multiple reeving with said main hook sheave whereby said main hook block depends from said main frame, a secondary hook block spaced from said main hook block and receiving said cable from one of said sheave means on both said axis remote from said drum and said intermediate axis whereby said secondary hook block depends from said main frame, locking means on said main frame releasably holding said main hook block thereto whereby to selectively hold said main block against movement relative to said frame, and means selectively operating said locking means whereby said main hook block is released against movement relative to said flame and means selectively operating said locking means.

4. A dual block hoist structure comprising a main crane frame, a hoisting drum on said, frame, drive means on the frame for driving the hoist drum, a cable on said drum extensible and retractable by rotation of said drum, three spaced parallel sheave axeson said frame generally parallel to and on one side of the drum forming an adjacent axis, an intermediate axis and a remote axis from said drum, sheave means on said adjacent axis, a main hook block, first sheave means on said main hook block receiving said cable from said drum, sheave means on said intermediate axisreceiving said cable from said first sheave means, sheavemeans on said remote axis receiving said cable from said sheave means on said intermediate axis, a secondary hook block spaced from said main hook block, sheave means on said secondary hook block receiving said cable from said sheave means on said remote axis and returning, said cable to second sheave means on said intermediate axis whereby said secondary hook block depends from said main frame,. second sheave means on said main hook blockreceiving said cable in multiple reeving with sheave means on said adjacent axis, lockingmeans on said main frame releasably holding said main hook block thereto whereby. to selectively hold said main block against movement relative to said frame, and means selectively operating said locking means.

5. A dual block hoist structure comprising a main crane frame, a hoisting drum on said frame, drive means onthe, frame for driving the hoist drum, a pair of cables on said drum extensible and retractable by rotation of said drum, three Spaced parallel sheave axes on said frame generally parallel to and on one side of the drum forming an adjacent axis, an intermediate axis'and a remote axis from said drum, sheave means on said adjacent axis, a mainhook block, first sheave means on" said main hook block receiving said cables from said drum, shea e means on said intermediate axisreceiving" said cables from said first sheave means, sheave means on 'said' remote axis receiving said cables-from said sheave means on said intermediate axis, a secondary hook block spaced from said main hookblock, sheave means on said secondary hook block receiving said'cables from said sheave means on said remote axis and returning said cables to frame, engaging said ends .of said'cables and equalizing relative variations-therein, locking means on said main frame releasably holding said main hook block thereto whereby to selectively hold said main block against movement relative to the frame, and means selectively operating said locking means.

6. A dual block hoist structure comprising a main crane frame, a hoisting drum on said frame, drive means on the frame for driving the hoist drum, a cable on said drum extensible and retractable by rotation of said drum, three spaced parallel sheave axes on said frame generally parallel to and on one side of the drum forming an adjacent axis, an intermediate axis and a remote axis from said drum, sheave means on said adjacent axis, a main hook block, first sheave means on said main hook block receiving said cable from said drum, sheave means on said intermediate axis receiving said cable from said first sheave means, sheave means on said remote axis receiving said cable fiom said sheave means on said intermediate axis, a secondary hook block spaced from said main hook block, sheave means on said secondary hook block receiving said cable from said sheave means on said remote axis and returning said cable to second sheave means on said intermediate axis whereby said secondary book block depends from said main frame, second sheave means on said main hook block receiving said cable in multiple reeving with sheave means on said adjacent axis, locking means on said main frame releasably holding said main hook block thereto whereby to selectively hold said main block against movement relative to said frame, a second locking means on said main frame releasably locking said secondary hook block against movement relative to said frame and means selectively operating said locking means.

7. A dual hook block hoist structure as claimed in claim 6, wherein interlocking means is provided on the frame, automatically, successively releasing the latches on the hook blocks as the hook blocks are ultimately raised to the frame.

Rodier Nov. 21, 1922 King Mar. 1, 1949 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,994,513 August 1, 1961 Myron R. Bowerman et; a1,

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent. should read as corrected below.

Column 1, line 35, for shaves" read sheaves column 3, line 45, before "main" insert said =8 Signed and sealed this 2nd day of January 1962,

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents uscoMM-oc 

